A new lepidopteran fossil from the Canyon Ferry Reservoir Deposit in southwestern Montana

Luikhart et al (1995) discovered and CoBabe et al (2002) recently published a detailed report of an insect and plant Lagerstaate from a Tertiary lake deposit along the Canyon Ferry Reservoir in southwestern Montana. The wide diversity of excellent quality Oligocene fossils includes representatives of 37 families of insects and more than 40 plant taxa. Among the insect fossils was well preserved forewing of a satyrine butterfly (Lepidoptera: Satyridae). A comparative analysis of extant taxa indicates that this specimen should be placed in the genus Lethe, and is of Beringian origin. The diagnostic features and evolutionary implications of this new fossil will be discussed.